package mapreduce;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
public class MyAverage {
    public static class Map extends Mapper < Object, Text, Text, IntWritable > {
        private static Text newKey = new Text();
        public void map(Object key, Text value, Context context) throws IOException,
        InterruptedException {
            String line = value.toString();
            System.out.println(line);
            String arr[] = line.split("\t");
            newKey.set(arr[0]);
            int click = Integer.parseInt(arr[1]);
            context.write(newKey, new IntWritable(click));
        }
    }
    public static class Reduce extends Reducer < Text, IntWritable, Text, IntWritable > {
        public void reduce(Text key, Iterable < IntWritable > values, Context context) throws IOException,
        InterruptedException {
            int num = 0;
            int count = 0;
            for (IntWritable val: values) {
                num += val.get();
                count++;
            }
            int avg = num / count;
            context.write(key, new IntWritable(avg));
        }
    }
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        Configuration conf = new Configuration();
        System.out.println("start");
        Job job = new Job(conf, "MyAverage");
        job.setJarByClass(MyAverage.class);
        job.setMapperClass(Map.class);
        job.setReducerClass(Reduce.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);
        Path in = new Path("hdfs://localhost:9000/mymapreduce4/in/goods_click");
        Path out = new Path("hdfs://localhost:9000/mymapreduce4/out");
        FileInputFormat.addInputPath(job, in );
        FileOutputFormat.setOutputPath(job, out);
        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }
}